What's the point with that quite lackluster story in Endwalker?

[CrownySuccubus]

7 was easily darker than 14 in almost every aspect. Between the plates falling, actual impactful character death etc.

I already said this. VI and VII are the darkest the mainline series has ever gotten, though FFXV comes damn close.

Well if its the standard why is 14 exempt from it and all the consequences like this? Even the final days didnt leave any impactful changes to the zones or cities.

It....doesn't? The Garleans almost go completely extinct in Endwalker alone.

Throughout the rest of FFXIV proper, the last of the Ancients goes extinct, the dragons are heavily endangered, with few of the First Brood remaining, Thavnair loses an unspecified number of its people, countless races on The First are extinct or barely hanging on by a thread (I guess we can count that as happening in the game itself, since the Flood of Light was an HW event), and I'm sure I'm forgetting a lot of stuff. (EDIT: Yeah, like the Umbral Calamity that literally changed the entire world -- the entire impetus between 1.0 and 2.0.)

But, for the long answer, FFXIV being a live service games makes it practically impossible for there to be heavy, long-term consequences to the world at large. The basic framework of the setting needs to be the same for new players as well as people who've completed the latest patch. Would be kinda awesomely tragic if you couldn't, say, pick Roegadyn anymore after some event in the game made them basically extinct as a species, but it would also be horribly unfair.